OBJECTIVE: Our long-term goals are to develop more sophisticated approaches to the study of lipid transport and its control in cancerous animals, to study the hormonal and nutritional control of fatty acid transport in a variety of experimental tumors, both in vivo and in vitro, to search for some unique fatty acid transport systems which may exist in cancerous mice, and to use information from these studies to develop efficient, predictable methods for altering the lipid composition of cancer cell membranes. Eventually, we shall try to increase the specific susceptibility of cancer cells to lipidic, anti-cancer agents by modifying the cancer cell membrane lipid composition using strategies derived from the above kinetic and metabolic studies. APPROACH: Various C14- and H3-labeled fatty acids complexed to albumin or incorporated into very low density lipoproteins are to be injected intravenously and intraperitoneally into mice bearing Ehrlich ascites carcinoma or an ascites melanoma. Rates of free fatty acid flux into the tumor cell lipids as well as rates of fatty acid oxidation to CO2 and H2O are to be estimated using complex tracer data, pool sizes, and multicompartmental analyses of the data. Effects of varying nutritional states on these parameters are also being studied. Studies will also be carried out using C14-labeled dietary fatty acids to determine the contribution of dietary lipid to tumor cell lipids (growth) and to the tumor cell's metabolic needs. In addition, in vitro experiments are to be carried out to see whether tumor cells produce substances that increase lipolysis in fat cells.